Visualization of multiple organ amyloid involvement in systemic amyloidosis using 11 C-PiB PET imaging

Abstract

Purpose

To investigate the utility of Pittsburgh compound B (PiB) positron emission tomography (PET) imaging for evaluating whole-body amyloid involvement in patients with systemic amyloidosis.

Methods

Whole-body ¹¹C-PiB PET was performed in seven patients with systemic immunoglobulin light-chain (AL) amyloidosis, seven patients with hereditary transthyretin (ATTRm) amyloidosis, one asymptomatic TTR mutation carrier and three healthy controls. The correlations between clinical organ involvement, radiological ¹¹C-PiB uptake and histopathological findings were analysed for each organ.

Results

Organ involvement on ¹¹C-PiB PET imaging showed good correlations with the clinical findings for the heart and stomach. Abnormal tracer uptake was also observed in the spleen, lachrymal gland, submandibular gland, sublingual gland, lymph node, brain, scalp, extraocular muscles, nasal mucosa, pharynx, tongue and nuchal muscles, most of which were asymptomatic. Physiological tracer uptake was universally observed in the urinary tract (kidney, renal pelvis, ureter and bladder) and enterohepatic circulatory system (liver, gallbladder, bile duct and small intestine) in all participants. Most of the patients and one healthy control subject showed asymptomatic tracer uptake in the lung and parotid gland. The peripheral nervous system did not show any tracer uptake even in patients with apparent peripheral neuropathy. Histological amyloid deposition was confirmed in biopsied myocardium and gastric mucosa where abnormal ¹¹C-PiB retention was observed.

Conclusions

¹¹C-PiB PET imaging can be used clinically in the systemic evaluation of amyloid distribution in patients with AL and ATTRm amyloidosis. Quantitative analysis of ¹¹C-PiB PET images may be useful in therapy evaluation and will reveal whether amyloid clearance is correlated with clinical response.

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